I waited for the release of the 290x's and 780 Tis before deciding and ..... in the end chose a pair of 780s ....
1. While not the fastest card outta the box, when overclocked "to the wall" the 780 tops everything but the 780 Ti
2. Some of em (i.e. Asus DCII) can easily handle 25% OC's or more..... The EVGA Classified and MSI Lightning even more but at more $.
http://uk.hardware.info/reviews/4639/10/nvidia-geforce-gtx-780-asus-vs-evga-vs-inno3d-vs-msi-conclusion
3. All other things being equal, I loved LightBoost so G-Sync compatibility was a big plus for our 144 Hz monitors....PhysX is like AC in a car .... no big deal in January but when it's available sure adds a lot to the experience. Shadowplay is important to many gamers but I don't much get excited about it.
Those other factors may be important to you....but it kinda matters what resolutions, what Hz ya monitors will be, whether you use any CUDA apps, whether you bitcoin mine, whether you plan on water cooling as block availability varies by manufacturer, etc. .... so depending on those answers whether ya go red or green will be in question.